package com.ruoyi;

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.ruoyi.jwyz.domain.Activity;
import com.ruoyi.jwyz.domain.UserAttendActivity;

import java.util.ArrayList;
import java.util.List;

public class Main {

    public static void main(String[] args) {

        List<Activity> activityList = new ArrayList<>();



        System.out.println("Hello world!");
        System.out.println(activityList);
        if (activityList.size()==0) {
            System.out.println("null");
        }
    }
}